干旱区生态环境知识资源中心(Arid): 西藏紫花针茅叶功能性状沿降水梯度的变化

Arid

	西藏紫花针茅叶功能性状沿降水梯度的变化
其他题名	Variations in leaf functional traits of Stipa purpurea along a rainfall gradient in Xizang,China
	胡梦瑶; 张林; 罗天祥; 沈维
来源期刊	植物生态学报
ISSN	1005-264X
出版年	2012
卷号	36 期号:2 页码:136-143
中文摘要	植物叶功能性状与环境因子的关系是近10年来植物生态学的研究热点。该文以广泛分布于青藏高原干旱、半干旱草地的优势植物种紫花针茅(Stipa purpurea)为研究对象,沿降水梯度(69-479mm)系统测定了日土、改则、珠峰、当雄和纳木错5个调查地点紫花针茅比叶面积(SLA)、单位重量和单位面积叶氮含量(N_(mass),N_(area))、叶密度和厚度等叶功能性状以及土壤全氮含量等因子,试图验证干旱胁迫地区同一物种内SLA-N_(mass)关系沿降水梯度的策略位移现象是否具有普遍性,并对是否出现策略位移现象提出可能的解释。研究结果表明:1)SLA和N_(mass)与生长季温度和降水以及土壤全氮含量均没有显著关系,SLA与N_(mass)的关系在干旱半干旱区(年降水/蒸发比<0.11)与半湿润区(年降水/蒸发比>0.11)之间并没有出现典型的位移现象;2)叶密度是决定半湿润区SLA变化的主导因子,而叶厚度则是干旱半干旱区SLA变化的控制因子,两者与SLA均呈负相关,随着温度增加或降水减少,叶厚度增加而叶密度降低,导致SLA随温度和降水变化不明显;3)半湿润区的叶密度增加引起N_(area)增加,而干旱半干旱区的叶厚度增加并没有造成N_(area)的显著变化,导致N_(area)沿降水梯度没有显著变化;4)紫花针茅地上生物量与N_(area)具有显著正相关关系,表明N_(area)的增加有助于提高植被生产力。结果表明,在干旱胁迫下,植物通过增加叶厚度来维持不变的N_(area)可能有助于保持与较湿润地区相似的光合生产和水分利用效率。叶厚度和叶密度对比叶面积的相对影响在干旱半干旱区与半湿润区之间发生转变,这为进一步检测高寒草地植被的水分限制阈值提供了新思路。
英文摘要	Aims Stipa purpurea is the dominant species in alpine arid and semi-arid grasslands on the Tibetan Plateau.Our objectives are to determine if this species exhibits a strategy shift in its specific leaf area(SLA) to nitrogen(N) concentration relationship along a rainfall gradient and to detect possible effects of environmental factors on re-lated leaf traits.Methods We investigated variations in leaf traits of S.purpurea associated with climatic and soil factors along an east-west transect with a rainfall gradient(69-479 mm) but similar altitudes(4 300-4 700 m).Five locations from east to west are Damxung,Namco,Gerze,Mount Qomolangma and Rutog.We measured SLA,mass-and area-based leaf N concentration(N_(mass),N_(area)),leaf density and thickness and soil total N along the transect.Important findings In pooled data,SLA and N_(mass) varied little with the growing season mean temperature and precipitation and the soil total N concentration.The SLA-N_(mass) relationship in S.purpurea did not shift between the semi-humid areas(ratio of rainfall to evaporation > 0.11) and the arid and semi-arid areas(ratio < 0.11),al-though there was a positive correlation between SLA and N_(mass) across the five locations.Variation in SLA was mainly determined by leaf density in the semi-humid areas and by leaf thickness in the arid and semi-arid areas;both were negatively correlated with SLA.With increasing temperature or declining precipitation,leaf density de-creased and leaf thickness increased,leading to non-significant relationships between SLA and climatic factors.The increase of leaf density in the semi-humid areas was correlated with the increase of N_(area),but the increase of leaf thickness in the arid and semi-arid areas did not lead to change of N_(area),resulting in unchanged Narea along the rainfall gradient.A positive correlation was detected between aboveground biomass and N_(area) in S.purpurea,indi-cating that increased N_(area) may increase plant productivity.Our findings suggest that alpine plants in arid and semi-arid areas may maintain a constant N_(area) by increased leaf thickness in order to achieve a similar photosyn-thetic productivity and water use efficiency compared to the relatively humid areas.The relative impacts of leaf density and leaf thickness on SLA shifted between the semi-humid areas and the arid and semi-arid areas,which may provide insight in detecting the threshold of water limitation in alpine grasslands.
中文关键词	叶密度 ; 叶氮含量 ; 叶厚度 ; 比叶面积 ; 紫花针茅 ; 策略位移
英文关键词	leaf density leaf nitrogen concentration leaf thickness specific leaf area Stipa purpurea strategy shift
语种	中文
国家	中国
收录类别	CSCD
WOS类目	PLANT SCIENCES
WOS研究方向	Plant Sciences
CSCD记录号	CSCD:4457846
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/228864
作者单位	中国科学院青藏高原研究所, 中国科学院青藏高原环境变化与地表过程重点实验室, 北京 100085, 中国
推荐引用方式 GB/T 7714	胡梦瑶,张林,罗天祥,等. 西藏紫花针茅叶功能性状沿降水梯度的变化[J],2012,36(2):136-143.
APA	胡梦瑶,张林,罗天祥,&沈维.(2012).西藏紫花针茅叶功能性状沿降水梯度的变化.植物生态学报,36(2),136-143.
MLA	胡梦瑶,et al."西藏紫花针茅叶功能性状沿降水梯度的变化".植物生态学报 36.2(2012):136-143.